Agricultural apparatus for sensing and providing feedback of soil property changes in real time

ABSTRACT

An agricultural system includes an agricultural row unit movable on a field between a first soil condition and a second soil condition, the first soil condition having a different soil hardness than the second soil condition. A down-pressure actuator applies an initial first pressure associated with the first soil condition. A soil-hardness sensing device is positioned at a distance D forward of the row unit and outputs a soil-hardness change signal when detecting a change from the first soil condition to the second soil condition. At least one memory device stores instructions that, when executed by at least one processor, cause the down-pressure actuator to change, in response to receiving the soil-hardness change signal, the initial first pressure to a different second pressure when the row unit encounters the second soil condition.

FIELD OF THE INVENTION

The present invention relates generally to agricultural equipment and, more particularly, to a row crop implement having a soil sensor for providing down-pressure control feedback in real time.

BACKGROUND OF THE INVENTION

In agricultural operations, it is known to measure a force exerted on gauge wheels of an agricultural implement (e.g., a row crop planter), with a load cell or some other device. Based on this force, a signal is transmitted to an actuator that exerts a down-pressure force on the implement. The signal causes the actuator to change the down-pressure force, in response to a change in soil conditions, and achieve a desired force on the row crop planter.

Moreover, it is common in agricultural operations for small, localized, and compacted soil areas to be formed by tire tracks, topography changes, or soil type. These compacted soil areas cause the soil conditions to change, for example, from a hard soil condition to a soft soil condition. Current agricultural systems, however, react to signals caused by a compacted soil area after the implement has already passed over that compacted soil area. As such, current agricultural systems fail to apply a correct level of pressure for the soil that is immediately beneath the implement. Instead, when a new soil condition is detected in a particular field location, current agricultural systems apply the level of pressure associated with the new soil condition either before or after the implement has passed the particular field location. This results in inefficient and/or improper soil preparation for agricultural applications, such as planting or tilling, which, in turn, causes a decrease in crop quality and volume.

SUMMARY OF THE INVENTION

In accordance with one embodiment, an agricultural system includes an agricultural row unit movable on a field between a first soil condition and a second soil condition, the first soil condition having a different soil hardness than the second soil condition. A down-pressure actuator applies an initial first pressure associated with the first soil condition. A soil-hardness sensing device is positioned at a distance D forward of the row unit and outputs a soil-hardness change signal when detecting a change from the first soil condition to the second soil condition. At least one memory device stores instructions that, when executed by at least one processor, cause the down-pressure actuator to change, in response to receiving the soil-hardness change signal, the initial first pressure to a different second pressure when the row unit encounters the second soil condition.

In accordance with another embodiment, an agricultural system includes a plurality of row units positioned in a side-by-side arrangement and attachable to a towing frame, the plurality of row units being movable on a field between soil conditions of varying soil hardness. The plurality of row units includes a first group of row units positioned inside a towing-vehicle width and a second group of row units positioned outside the towing-vehicle width. A hydraulic actuator is mounted on and applies down pressure to each row unit of the plurality of row units, the hydraulic actuator being adjustable to a frequency F and initially applying a first down pressure. A first soil-hardness sensing device is positioned at a distance X1 forward of at least one row unit of the first group of row units, the first soil-hardness sensing device outputting a first soil-hardness change signal when detecting a change in soil hardness inside the towing-vehicle width. A second soil-hardness sensing device is positioned at a distance X2 forward of at least one row unit of the second group of row units, the second soil-hardness sensing device outputting a second soil-hardness change signal when detecting a change in soil hardness outside the towing-vehicle width. At least one memory device stores instructions that, when executed by one or more processors, cause the hydraulic actuator of respective ones of the plurality of row units to change, in response to receiving at least one of the first soil-hardness change signal and the second soil-hardness change signal, the first pressure to a second pressure.

In accordance with yet another embodiment, an agricultural system includes an agricultural row unit movable on a field between a first soil condition and a second soil condition, the first soil condition having a different soil hardness than the second soil condition. A down-pressure actuator applies pressure to the row unit, the down-pressure actuator initially applying a first pressure associated with the first soil condition. A velocity sensing device detects a velocity Q of the row unit. A soil-hardness sensing device is positioned at a distance D forward of the row unit and encounters the second soil condition at an initial time prior to the row unit encountering the second soil condition at a subsequent time. The soil-hardness sensing device outputs a soil-hardness change signal when detecting a change from the first soil condition to the second soil condition. At least one memory device stores instructions that, when executed by at least one processor, cause the down-pressure actuator to change, in response to receiving the soil-hardness change signal and based on the velocity Q and the distance D, the first pressure to a second pressure at the subsequent time when the row unit encounters the second soil condition.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a soil-hardness sensing device attached to a planting row unit.

FIG. 2 is a schematic side elevation illustrating the soil-hardness device attached to the planting row unit.

FIG. 3 is a schematic diagram illustrating the determination of hydraulic pressures for a planting row unit.

FIG. 4A is a side elevation of an agricultural system moving over soft soil conditions.

FIG. 4B is a side elevation of the agricultural system of FIG. 4A in which a soil-hardness sensing device is moving over hard soil conditions.

FIG. 4C is a side elevation of the agricultural system of FIG. 4B in which a planting row unit is moving over the hard soil conditions.

FIG. 5A is a schematic side elevation illustrating sensing of soil conditions and determining of hydraulic pressures for a planting row unit.

FIG. 5B is a flowchart of an algorithm for adjusting a pressure applied to a soil-hardness sensing device.

FIG. 5C is a flowchart of an algorithm for adjusting a user-defined variable associated with a pressure applied to a planting row unit.

FIG. 5D is a flowchart of an algorithm for adjusting a user-defined variable associated with a pressure applied to a row-clearing unit.

FIG. 6A is a top elevation illustrating an agricultural system in which a plurality of planting row units are adjusted by two soil-hardness sensing devices.

FIG. 6B is a side elevation illustrating the agricultural system of FIG. 6B.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Although the invention will be described in connection with certain preferred embodiments, it will be understood that the invention is not limited to those particular embodiments. On the contrary, the invention is intended to cover all alternatives, modifications, and equivalent arrangements as may be included within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1, an agricultural system 100 includes a soil-hardness sensing device 102 attached in front of an agricultural row unit 104 (also referred to as a planting row unit) via a towing frame 106. The towing frame 106 is generally a common elongated hollow frame that is typically hitched to a tractor by a draw bar. The towing frame 106 is rigidly attached to a front frame 108 of a four-bar linkage assembly 110 that is part of the row unit 104. The four-bar (sometimes referred to as “parallel-bar”) linkage assembly 110 is a conventional and well known linkage used in agricultural implements to permit the raising and lowering of tools attached thereto.

As the planting row unit 104 is advanced by the tractor, a pair of cooperating toothed clearing wheels 122 work the soil and then other portions of the row unit, such as a V-opener disk 112, part the cleared soil to form a seed slot, deposit seed in the seed slot and fertilizer adjacent to the seed slot, and close the seed slot by distributing loosened soil into the seed slot with a closing wheel 114. According to one example, the closing wheel 114 is a CUVERTINE™ closing wheel sold by the assignee of the present application. The CUVERTINE™ closing wheel is an efficient toothed wheel in-between a spading wheel and a rubber wheel.

A gauge wheel 116 of the planting row unit 104 determines the planting depth for the seed and the height of introduction of fertilizer, etc. One or more bins 118 on the planting row unit 104 carry the chemicals and seed that are directed into the soil.

The planting row unit 104 is urged downwardly against the soil by its own weight. To increase this downward force, or to be able to adjust the force, a hydraulic or pneumatic actuator 120 (and/or one or more springs) is added between the front frame 108 and the four-bar linkage assembly 110 to urge the planting row unit 104 downwardly with a controllable force. Such a hydraulic actuator 120 may also be used to lift the row unit off the ground for transport by a heavier, stronger, fixed-height frame that is also used to transport large quantities of fertilizer for application via multiple residue-clearing and tillage row units. According to one example, the hydraulic actuator 120 is an RFX™ system sold by the assignee of the present application. The RFX™ system includes a down-pressure actuator that is a compact, fast action actuator, and that is remotely controlled. The RFX™ system includes an nitrogen pressure-vessel that is integrated with the down-pressure actuator. According to other examples, the hydraulic or pneumatic actuator 120 may be controlled to adjust the downward force for different soil conditions such as is described in U.S. Pat. Nos. 5,709,271, 5,685,245 and 5,479,992.

The planting row unit 104 further includes a row-clearing unit 122 having a pair of rigid arms 124 adapted to be rigidly connected to the towing frame 106. According to one example, the row-clearing unit 122 is a GFX™ system (i.e., ground effects row cleaner), which is sold by the assignee of the present application, that is a hydraulically-controlled row cleaner. The GFX™ system is a hydraulically-controlled row cleaner with spring upward pressure and hydraulic down pressure. Furthermore, the GFX™ system is remotely adjusted.

At the bottom of the row-clearing unit 122, the pair of cooperating toothed clearing wheels 126 are positioned upstream of the V-opener disk 112 of the planting row unit 104. The clearing wheels 126 are arranged for rotation about transverse axes and are driven by the underlying soil as the wheels are advanced over the soil. The illustrative clearing wheels 126 are a type currently sold by the assignee of the present invention under the trademark TRASHWHEEL™. The clearing wheels 126 cooperate to produce a scissors action that breaks up compacted soil and simultaneously clears residue out of the path of planting. The clearing wheels 126 kick residue off to opposite sides, thus clearing a row for planting. To this end, the lower edges are tilted outwardly to assist in clearing the row to be planted. This arrangement is particularly well suited for strip tilling, where the strip cleared for planting is typically only about 10 inches of the 30-inch center-to-center spacing between planting rows.

The soil-hardness sensing device 102 has a first linkage 130 with an attached blade 132 and a second linkage 134 with an attached gauge wheel 136. According to one example, the linkages are medium FREEFARM™ linkages sold by the assignee of the present application. The FREEFARM™ linkages are generally a modular set of parallel linkages used for different purposes. Also, according to one example, the soil-hardness sensing device 102 is a FORESIGHT AND CFX™ ground hardness sensor that is sold by the assignee of the present application.

The two linkages 130, 134 are parallel to each other and each has a down pneumatic pressure that is controlled independently. Under constant pneumatic pressure, when the soil-hardness sensing device 102 is moved through the field, the blade 132 penetrates the soil deeper in soft soil and shallower in hard soil. However, the wheel 136 rides on the soil surface regardless of the type of soil.

Each linkage 130, 134 has a high quality all-stainless steel linear position sensor 138, 140 enclosed in a protecting housing, with a cable 142, 144 routed to a central processing unit (CPU) 146, which includes a memory device for storing instructions and at least one processor for executing the instructions. When the blade 132 or the wheel 136 moves, a corresponding change in value is recorded on the respective position sensors 138, 140. The two values from the position sensors 138, 140 are outputted as fast as approximately 1,000 times/second and are fed as soil-hardness signals to the CPU 146, which is a rugged outdoor-rated programmable logic controller that measures the difference in the two values in real time.

In the illustrated example, the CPU 146 is positioned on the planting row unit 104. However, in other embodiments the CPU 146 may be positioned remote from the planting row unit 104, e.g., in a tractor cabin, on a different planting row unit of a side-by-side row unit arrangement, etc. Furthermore the processor and the memory device of the CPU 146 can be located in the same place, e.g., on the planting row unit 104, or in different places, e.g., the processor can be located on the planting row unit 104 and the memory device can be located in the tractor cabin.

The CPU 146 averages the values over a predetermined time period (e.g., 0.25 seconds), executes an algorithm with filtering effects (e.g., removes conditions in which a rock is hit by the soil-hardness sensing device 102), and provides real-time measurement of the soil hardness. The CPU 146 optionally receives other user-controllable variables for adjusting/tuning the agricultural system 100. For example, the user-controllable variables include values for different residue levels, different initial conditions, etc.

Referring to FIG. 2, the agricultural system 100 receives hydraulic fluid from a hydraulic source, typically located in the tractor, at a hydraulic input pressure P0. The hydraulic fluid is directed to each one of a plurality of hydraulic control valves V1-V3. The CPU 146 outputs a respective signal S1-S3 to the control valves V1-V3, which create a proportional output/change in the pressure of hydraulic circuits, virtually instantaneously changing the pressure in real time as the agricultural system 100 moves through a field. The pressure changes are useful, for example, when the agricultural system 100 encounters hardened soil areas in which combines or grain carts have previously compacted the soil. The agricultural system 100 optimizes the pressure to achieve a desired depth control by applying the right amount of pressure at the right time.

To achieve the right amount of pressure for each controllable component (e.g., the hydraulic actuator 120, the row-clearing unit 122, and the soil-hardness sensing device 102), the CPU 146 outputs the respective signals S1-S3 to the associated control valves V1-V3. For example, in response to receiving a first signal S1 from the CPU 146, a first control valve V1 outputs a proportional first pressure P1 to the hydraulic actuator 120 (e.g., RFX™ system) for urging the planting row unit 104 downwardly. Similarly, in response to receiving a second signal S2 from the CPU 146, a second control valve V2 outputs a proportional second pressure P2 to the row-clearing unit 122 (e.g., GFX™ system). The RFX™ system 120 and the GFX™ system 122 are controlled independently because residue typically exhibits non-linear behavior. In other words, the independent control of the two systems 120, 122 is likely to achieve better depth-control results.

A third control valve V3 receives a third signal S3 from the CPU 145, in response to which the third control valve outputs a proportional third pressure P3 to the soil-hardness sensing device 102 (e.g., FORESIGHT AND CFX™ system). The control valves V1-V3 return hydraulic fluid to the hydraulic source at a return pressure PR. Respective transducers for each of the control valves V1-V3 may be used to verify that hydraulic output matches the desired value. If the hydraulic output does not match the desired value, the hydraulic output is corrected. Furthermore, each of the control valves V1-V3 has a respective valve response time T1-T3, which are discussed in more detail below in reference to determining the timing of applying the appropriate pressures P1-P3.

The CPU 146 further receives an input speed signal SQ indicative of a speed Q of the agricultural system 100, which moves typically at about 6 miles per hour, i.e., about 8.8 feet per second. As discussed in more detail below, the speed signal SQ is used to determine the values of pressures P1-P3 based on current soil conditions. Furthermore, as discussed in more detail below, the CPU 146 further outputs two signals, a sensor signal SCFX to the soil-hardness sensing device 102 and a closing wheel SCW to the closing wheel 114.

The soil-hardness sensing device 102 is positioned in front of the planting row unit 104 at a distance D (which is measured generally from a center line of the blade 132 to a center line of the V-opener disk 112), which can be obtained based on the following formula: Q (speed)=D (distance)/T (time interval)   Equation 1 Thus, the distance D is calculated as follows: D=Q*T   Equation 2

If D is a known distance (e.g., the distance between the sensed position and position where seed-depositing position) and the speed Q is also known, changes in soil conditions can be anticipated in real time prior to the planter row unit 104 arriving to the particular soil-change area. For example, assuming that Q is approximately 8.8 feet per second and T is approximately 0.25 seconds, D should be approximately equal to or greater than 2.2 feet. In other words, the minimum distance for D should be approximately 2.2 feet. If D is greater than the minimum value (e.g., D is greater than 2.2 feet), the agricultural system 100 is calibrated to account for the additional distance. For example, the CPU 146 will send the respective signals S1, S2 to the associated control valves V1, V2 only after a predetermined period of time Tact, as discussed in more detail below.

Pressures P1 and P2 are to be applied only when matched with the corresponding soil conditions. For example, P1 and P2 are increased exactly at the time when harder soil conditions are encountered directly below the planting row unit 104. To properly time the change in pressures P1 and P2 correctly, a time variable R refers to the latent processing speed of CPU 146 and accounts for the time between (a) receiving an input signal by the CPU 146, (b) sending output signals S1, S2 by the CPU 146, and (c) responding to the output signals S2, S2 by the control valves V1, V2 with respective outputting pressures P1, P2.

It is noted that each of the control valves V1, V2 has a minimum input time Tmin, and that the distance D (e.g., as measured between the center of the blade 232 and the center of the V-opener disk 212) is directly proportional to the speed Q multiplied by the minimum input time Tmin of the respective control valve V1, V2. It is further noted that a theoretical time Ttheor is directly proportional to the distance D divided by the speed Q (i.e., D/Q), and that an actual time Tact is directly proportional to the theoretical time Ttheor minus the time variable R (i.e., Ttheor−R). Based on these conditions, for outputting pressures P1 and P2, the CPU 146 holds in memory output signals S1 and S2 for a time duration that is equal to the actual time Tact. After the actual time Tact has elapsed, the CPU 146 outputs signals S1 and S2, respectively, to the control valves V1, V2, which respond by outputting pressures P1, P2. Optionally, signals S1 and S2 are outputted as signals ranging between 0-10 volts.

Referring to FIG. 3, a global positioning system (GPS) provides a GPS signal indicative of the speed Q to the tractor. Optionally, for example, the speed Q can be generated from a radar system. The speed Q is inputted to the CPU 146, along with the soil-hardness signals received from the position sensors 138, 140. Based on the speed Q and the soil-hardness signals, the CPU 146 outputs signals Si and S2 to the control valves V1, V2, which output proportional pressures P1 and P2 for adjusting, respectively, the RFX™ system 120 and the GFX™ system 122.

Referring to FIGS. 4A-4C, the agricultural system 100 encounters various types of soil-hardness conditions, which, for ease of understanding, will include soft soil conditions and hard soil conditions. The soft soil conditions exemplify typical soil conditions, and the hard soil conditions exemplify compacted soil areas, e.g., areas compacted by tire tracks of tractors or combines.

Referring specifically to FIG. 4A, the agricultural system 100 is moving forward at a speed Q over an initial soil area having only soft soil conditions. Based on the soft soil, the blade 132 penetrates the soil at a distance X1 lower than the wheel 136 (which rides on the soil surface). The distance X1 is the difference between the position sensors 138, 140. In accordance with the distance X1, which is associated with soft soil conditions, corresponding pressures P1 and P2 are applied to the hydraulic actuator 120 and the row-clearing unit 122.

Referring specifically to FIG. 4B, the blade 132 and the wheel 136 (but not the planting row unit 104) are now moving over a soil area of hard soil conditions. Because the soil is now much harder than the previous soil area, the blade 132 cannot penetrate the soil as much as in the previous soil area. As such, the blade 132 rises higher relative to the soil surface and penetrates the soil only at a distance X2 lower than the wheel 136 (which continues to ride on the soil surface). The distance X2 is the distance determined by the CPU 146 based on the corresponding change in value outputted by the position sensors 138, 140. However, although the distance X2 (which is associated with hard soil conditions) is different than the previous distance X1 (which is associated with soft soil conditions), the corresponding pressures P1 and P2 are not changed, yet, because the planting row unit 104 has not reached the hard-soil area.

Referring specifically to FIG. 4C, the planting row unit 104 is now moving over the hard-soil area, which the blade 132 and the wheel 136 have already passed. At this point in time, and only at this point in time, the pressures P1 and P2 are increased to maintain the desired depth level. Thus, although the soil-hardness sensing device 102 has reached, again, soft soil conditions that allow the blade 132 to penetrate the soil at the previous distance X1, the pressures P1 and P2 are adjusted in accordance with the hard soil conditions.

Referring to FIG. 5A, another exemplary soil-hardness sensing device 202 is attached to a towing frame 206 and includes a planting row unit 204 having a V-opener disk 212, a closing wheel 214, and a row-unit gauge wheel 216. The planting row unit 204 further includes a hydraulic actuator 220 that responds to a pressure P1 and a row-clearing unit 222 that responds to a pressure P2. The soil-hardness device 202 and the planting row unit 204 are generally similar to the soil-hardness device 102 and the planting row unit 104 described above in reference to FIGS. 1-4C, except for any changes described below.

In this embodiment the soil-hardness device 202 can be a device that is already included in the planting row unit 204, such as a cutting coulter running directly in-line with the planter row unit or a fertilizer opener positioned off to a side of the planted area. Thus, assuming a side-by-side arrangement of row units, the soil-hardness device can take the form of a fertilizer opener or a no-till cutting coulter in front of or to the side of every row unit.

The soil-hardness device 202 includes a blade 232 and a soil-hardness gauge wheel 236. The blade 232 is attached to a blade arm 260 and the soil-hardness gauge wheel 236 is attached to a wheel arm 262. The wheel arm 262 is biased down by a spring 264 and pivots relative to the blade arm 260. An angular encoder 266 measures changes in an angle θ between the blade arm 260 and the wheel arm 262. The angle θ is directly proportional to the depth of the blade 232 relative to the soil-hardness gauge wheel 236.

The angle θ is sent to a CPU 246 which executes an algorithm to determine corresponding pressure values for the planting row unit 204. A minimum angle θmin is equal to angle θ when both the blade 232 and the soil-hardness gauge wheel 236 are on the soil surface, e.g., when passing over very hard soil conditions or a concrete floor. A depth variable Z indicates a desired blade depth, i.e., blade 232 penetration into the soil. The angle θ is directly proportional to the depth variable Z, which has a range between an actual (or current) depth value Zact and a theoretical depth value Ztheor.

By way of comparison, in the soil-hardness device 202 of the current embodiment a controllable pressure P3, which is applied to the soil-hardness device 202, is varied, but the angle θ between the blade 232 and the soil-hardness gauge wheel 236 is maintained generally constant, with the blade 232 penetrating the soil at a desired blade depth Z. In contrast, in the soil-hardness device 102 described above in reference to FIGS. 4A-4C the difference between the blade 132 and the wheel 136 is varied (e.g., distances X1 and X2), but the pressure applied to the soil-hardness device 102 is maintained generally constant.

According to one aspect of the algorithm illustrated in FIG. 5B, the angle θ is measured (270A) and the actual depth value Zact is calculated (270B). Based on the actual depth value Zact and an inputted theoretical depth value Ztheor (270C), a determination is made whether the actual depth value Zact is equal to the theoretical depth value Ztheor (270D): If Zact=Ztheor=>end   Equation 3 If the actual depth value Zact is equal to the theoretical depth value Ztheor (i.e., Zact=Ztheor), the algorithm ends (until the next value is received) (270H). Optionally, if angle θ is less than minimum angle θmin (i.e., θ<θmin), algorithm ignores changes because those values typically illustrate that the soil-hardness sensing device 202 has hit a rock.

If the actual value of the depth variable Z is greater than the theoretical value of the depth variable Z (i.e., Zact>Ztheor) (270E), the controllable pressure P3 that is being applied to the soil-hardness device 202 is decreased until the actual value of the depth variable Z is equal to the theoretical value of the depth variable Z (i.e., Zact=Ztheor) (270F): If Zact>Ztheor=>decrease P3 until Zact=Ztheor   Equation 4 If the actual value of the depth variable Z is smaller than the theoretical value of the depth variable Z (i.e., Zact<Ztheor), then the controllable pressure P3 is increased until the actual value of the depth variable Z is equal to the theoretical value of the depth variable Z (i.e., Zact=Ztheor) (270G): If Zact<Ztheor=>increase P3 until Zact=Ztheor   Equation 5

Thus, according to this algorithm, the desired depth Z of the blade 232 is maintained constant by varying the pressure P3 in response to detected changes in the angle θ. To vary the pressure P3, a user-defined variable M (similar to the user-defined variables K and J described below) is increased or decreased to modify an actual value P3act of the pressure P3 until the desired depth variable Z is achieved. As such, assuming that a theoretical value P3theor of the pressure P3 is being applied to the blade 232 when the desired depth Ztheor is achieved, and further assuming that P3theor is directly proportional to M*P3act, M is modified until M*P3act is equal to P3theor (and, consequently, the desired depth variable Z is achieved). For example, if the depth variable Z is too small, i.e., the blade 232 is running too shallow into the soil (e.g., the blade 232 is moving through a heavily compacted soil area), as detected by a change in the angle θ, M is increased until the actual pressure value P3act is equal to the theoretical value P3theor. Once the theoretical value P3theor is reached, the increased pressure forces the blade 232 into the soil at the desired depth. Furthermore changes to the pressure P1 and the pressure P2 can be effected based on M*P3act being directly proportional to P1 and P2.

According to another aspect of the algorithm, illustrated in FIG. 5C, if feedback is desired from the row-unit gauge wheel 216, to verify that the system is performing as desired (e.g., to verify that the appropriate pressure values are being applied to the planting row unit 204), a weight variable W is set in accordance with a desired weight. In this example, the pressure P1 applied to the hydraulic actuator 220 of the planting row unit 204 is directly proportional to a user-defined variable K multiplied by the pressure P3 applied to the soil-hardness device 202 (i.e., P1 is directly proportional to K*P3).

A signal S4 (illustrated in FIG. 5A), which is directly proportional to the weight variable W, is outputted by a gauge wheel load sensor 280 (illustrated in FIG. 5A) and averaged over a time period Tgauge. After measuring the actual weight value Wact (272A) and receiving the theoretical weight value Wtheor (272B), a determination is made whether the actual weight value Wact is equal to the theoretical weight value Wtheor (272C): If Wact=Wtheor=>end   Equation 6 If the actual weight value Wact is equal to the theoretical weight value Wtheor (i.e., Wact=Wtheor), the algorithm ends (272G) until the next measurement.

If the actual weight value Wact is greater than the theoretical weight value Wtheor (i.e., Wact>Wtheor), then the user-defined variable K is decreased (272E) until the actual weight value Wact is equal to the theoretical weight value Wtheor: If Wact>Wtheor=>decrease K   Equation 7

If the actual weight value Wact is less than the theoretical weight value Wtheor (i.e., Wact<Wtheor), then the user-defined variable K is increased (272F) until the actual weight value Wact is equal to the theoretical weight value Wtheor: If Wact<Wtheor=>increase K   Equation 8 The user-defined variable K can be set manually by a user or automatically via a load pin 282.

Similarly, referring to FIG. 5D, the pressure P2 applied to the row-cleaner unit 222 can be adjusted by adjusting a user-defined variable J. Specifically, in this example, the pressure P2 is directly proportional to the user-defined variable J multiplied by the pressure P3 (i.e. P2 is directly proportional to J*P3). After measuring the actual weight value Wact (274A) and receiving the theoretical weight value Wtheor (274B), a determination is made whether the actual weight value Wact is equal to the theoretical weight value Wtheor (274C): If Wact=Wtheor=>end   Equation 9 If the actual weight value Wact is equal to the theoretical weight value Wtheor (i.e., Wact=Wtheor), the algorithm ends (274G) until the next measurement.

If the actual weight value Wact is greater than the theoretical weight value Wtheor (i.e., Wact>Wtheor), then the user-defined variable J is decreased (274E) until the actual weight value Wact is equal to the theoretical weight value Wtheor: If Wact>Wtheor=>decrease J   Equation 10

If the actual weight value Wact is less than the theoretical weight value Wtheor (i.e., Wact<Wtheor), then the user-defined variable J is increased (274F) until the actual weight value Wact is equal to the theoretical weight value Wtheor: If Wact<Wtheor=>increase J   Equation 11 The user-defined variable J can also be set manually by a user or automatically via the load pin 282.

Referring to FIGS. 6A and 6B, an agricultural system 300 includes a tractor 301, two soil-hardness sensing devices 302A, 302B, a planting device 303, and a plurality of planting row units 304A-304L, which are configured in a side-by-side arrangement. In this example, each of the planting row units 304A-304L has at least one respective control Valve A-L, which is adjustable based on signals received from the soil-hardness sensing devices 302A, 302B.

The tractor 301 moves at a speed Q, pulling the soil-hardness sensing device 302A, 302B, the planting device 303, and the planting row units 304A-304L along a soil area that includes five soil areas 305A-305E. Specifically, the soil areas 305A-305E includes a top outside area 305A, a top wheel area 305B, a central area 305C, a bottom wheel area 305D, and a bottom outside area 305E. The top wheel area 305B and the bottom wheel area 305D have soil conditions that are harder than the top outside area 305A, the central area 305C, and the bottom outside area 305E. The harder soil conditions are caused by the wheels of the tractor 301 and/or planting device 303, which form a compacted path as the tractor 301 moves along the soil area. Thus, each of the top wheel area 305B and the bottom wheel area 305D are areas compacted by the wheels of vehicles.

A first soil-hardness sensing device 302A controls only the planting row units 304E, 304H that are positioned inside the compacted paths of the top wheel area 305B and the bottom wheel area 305D. A second soil-hardness sensing device 302B controls all the other planting row units 304A-304D, 304F-304G, and 304I-304L, i.e., all the planting row units positioned outside the compact paths of the top wheel area 305B and the bottom wheel area 305D (and within the top outside area 305B, the central area 305C, and the bottom outside area 305E). Optionally, any number of soil-hardness sensing devices and any number of planting row units can be used. For example, each of the planting row units 304A-304L can have its own designated soil-hardness sensing device.

The soil-hardness sensing devices 302A, 302B are positioned at a distance D in front of the planting row units 304A-304L. Optionally, each of the soil-hardness sensing devices 302A, 302B can be positioned at a different distance in front of the planting row units 304A-304L. For example, the first soil-hardness sensing device 302A can be positioned at a distance X1 in front of the planting row units 304A-304L and the second soil-hardness sensing device 302B can be positioned at a distance X2 in front of the planting row units 304A-304L. As currently illustrated in FIGS. 6A-6B, the distances X1 and X2 are equal to each other (being effectively distance D). Furthermore, the first soil-hardness sensing device 302A is positioned inside the compacted path of the bottom wheel area 305D and the second soil-hardness sensing device 302B is positioned inside the bottom outside area 305E (i.e., outside the compacted path of the bottom wheel area 305D).

The soil-hardness sensing devices 302A, 302B and the attached planting row units 304A-304L are generally configured to sense soil conditions and adjust corresponding hydraulic pressures of Valves A-L as described above in reference to FIGS. 1-5. The configuration of having multiple soil-hardness sensing devices 302A, 302B increases precision in adjustment of hydraulic pressures, based on current soil conditions, because it accounts for differences between compacted and non-compacted paths in a field that is being planted. Thus, for example, the soil-hardness sensing devices 302A, 302B provides signals to corresponding control valves for increasing and/or decreasing hydraulic pressures of the planting row units 304A-304L.

The soil-hardness sensing devices discussed above can be remotely controlled. For example, the soil-hardness sensing devices 302A, 302B can be remotely controlled with a handheld radio-frequency remote controller. By way of example, the remote controller can be used to manually increase and/or decrease the hydraulic pressures in one or more of the soil-hardness sensing devices 302A, 302B.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrated embodiment and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 

The invention claimed is:
 1. An agricultural system comprising: an agricultural row unit movable on a field between a first soil condition and a second soil condition, the first soil condition having a different soil hardness than the second soil condition; a down-pressure actuator applying pressure to the row unit, the down-pressure actuator initially applying a first pressure associated with the first soil condition; a soil-hardness sensing device positioned at a distance D forward of the row unit, the soil-hardness sensing device outputting a soil-hardness change signal when detecting a change from the first soil condition to the second soil condition; and at least one memory device storing instructions that, when executed by at least one processor, cause the down-pressure actuator to change, in response to receiving the soil-hardness change signal, the first pressure to a second pressure when the row unit encounters the second soil condition.
 2. The agricultural system of claim 1, wherein the soil-hardness change signal is determined based on the distance D and a velocity Q of the row unit.
 3. The agricultural system of claim 1, wherein the down-pressure actuator includes a hydraulic actuator.
 4. The agricultural system of claim 3, further comprising a control valve for controlling, in response to the soil-hardness change signal, flow of hydraulic fluid to the hydraulic actuator.
 5. The agricultural system of claim 1, wherein the at least one processor is located on the row unit.
 6. The agricultural system of claim 1, wherein the soil-hardness sensing device includes a first linear position sensor coupled to a blade and a second linear position sensor coupled to a wheel gauge, the soil-hardness change signal being determined in part based on relative motion between the blade and the wheel gauge as measured by the first linear position sensor and the second linear position sensor.
 7. The agricultural system of claim 1, wherein the soil-hardness sensing device includes a blade arm, a gauge wheel arm, and an angular encoder, the angular encoder measuring relative angular motion between the blade arm and the gauge wheel arm, the soil-hardness change signal being determined at least in part based on the relative angular motion.
 8. The agricultural system of claim 1, further comprising a side-by-side arrangement of agricultural row units connected to a towing frame, the row units including a first group of row units and a second group of row units, the first group of row units being positioned inside a compacted path formed by wheels of a towing vehicle, the second group of row units being positioned outside the compacted path.
 9. The agricultural system of claim 8, further comprising: another soil-hardness sensing device positioned outside the compacted path, the soil-hardness sensing device being positioned inside the compacted path; a first set of control valves for controlling, in response to the soil-hardness change signal, flow of hydraulic fluid to the first group of row units; and a second set of control valves for controlling, in response to another soil-hardness change signal outputted by the another soil-hardness sensing device, flow of hydraulic fluid to the second group of row units.
 10. An agricultural system comprising: a towing frame for attachment to a towing vehicle draw bar; an agricultural row unit attached to the towing frame in a trailing position relative to a moving direction on a field, the row unit being movable between a first soil condition and a second soil condition, the first soil condition having a different soil hardness than the second soil condition, the row unit including a down-pressure actuator for applying pressure to the row unit, the down-pressure actuator initially applying a first pressure associated with the first soil condition; a soil-hardness sensing unit attached to the towing frame in a forward position relative to the moving direction on the field, the soil-hardness sensing unit being positioned at a distance D forward of the row unit, the soil-hardness sensing unit detecting soil-hardness changes and outputting a soil-hardness change signal when detecting a change from the first soil condition to the second soil condition; and at least one memory device storing instructions that, when executed by at least one processor, cause the down-pressure actuator to change, in response to receiving the soil-hardness change signal, the first pressure to a second pressure when the row unit encounters the second soil condition.
 11. The agricultural system of claim 10, wherein the soil-hardness sensing unit is an integral unit separate from the row unit, the soil-hardness sensing unit detecting the soil-hardness changes independent of the row unit.
 12. The agricultural system of claim 10, wherein the soil-hardness change signal is determined in real time.
 13. The agricultural system of claim 10, wherein the soil-hardness change signal is based on the distance D and a velocity Q of the row unit.
 14. The agricultural system of claim 10, wherein the soil-hardness sensing unit is an integral unit separate from the row unit, the soil-hardness sensing unit detecting the soil-hardness changes independent of the row unit and in real time based on the distance D and a velocity Q of the row unit. 